fade

Fade is a continuous transition from one state to another.

The term is used in audio and video to refer to fading. When one audio or video signal fades continuously to another. In this context, one speaks of fade-in or fade-out, depending on whether one fades something in or out.

The function is also known from car radios for adjusting the volume between the front and rear speakers. The potentiometers used for fading are called fade controllers or faders.